The invention relates to a lightweight dual-face composite heddle frame slat for use on a loom. Typically, heddle frame slats are utilized in the construction of a heddle frame on a loom to support the heddle rods. The heddle frame includes a top frame slat and a bottom frame slat which are spaced apart in the frame by a pair of side frame members. The individual heddles are slidably carried on the heddle rods and supported in the frame having heddle eyes through which the warp yarns are threaded. The heddle frame raises and lowers the threads to create an open space called a shed through which the weft yarn is inserted during weaving.
In lifting the warp threads in the shedding motion during weaving, the heddle frame undergoes forces in two basic directions. First, the heddle frame encounters forces in the vertical direction while lifting the threads which produces a bending motion on the frame slat. Secondly, the heddle frame undergoes a front-to-back bending motion during beat-up of the fabric during which the reed beats the last pick of the weft yarn forward toward the fell of the fabric. These forces tend to bow the frame slats forwardly.
Typically, when heddle frames reach a length of one hundred inches or more, it has been necessary to add a center brace to the frame in order that it have sufficient stiffness to accommodate these forces.
Furthermore, with the advent of higher speed looms, the inertial loading on the heddle frames during shedding and beat-up motions is greatly increased. With the increased inertial forces acting on the heddle frame, there is an increased tendency of the heddle frame and hence frame slats to flex beyond the load imposed by warp threads and heddles. During the shedding and beat-up motions, once the heddle frame moves to the end of the stroke, there is a tendency for the free portions of the frame slat to continue moving because of inertia and the heavier it is the more that tendency is increased. The heavy weight of the longer heddle frames frequently render them unsuitable for the manual lifting in and out by the loom fixers. The increased weight makes the heddle frame difficult for the loom fixers to handle in the servicing and operation of the loom. The heavy weight of the frame is also detrimental to the life of the loom parts and the driving elements and linkages for the drive which drives the heddle frame.
Therefore, there is a need to provide a more lightweight heddle frame for high speed looms to lessen the inertial forces.
Typically, heddle frames having lengths of one hundred inches or more have required a center brace for stiffening the heddle frame and frame slats to accommodate the inertial and other loading forces during operation. With a center brace placed between the threads, a marking of the fabric being woven is often produced by the brace. The center brace is an additional expense and the installation and maintenance of the center brace is an additional and constant difficulty for the operator.
Heretofore, attempts have been made to provide more lightweight frames such as disclosed in U.S. Pat. Nos. 4,144,910 and 4,112,980. These devices have utilized the typical tubular construcion of the frame slat with reinforcing material added to the hollow portion of the frame slat. The heddle rod is attached to a depending flange which is secured in a conventional manner.
Netherlands Pat. No. 6,913,347 discloses a similar concept of a heddle frame slat wherein a tubular construction is provided filled with a reinforcing material such as foam plastic. Swiss Pat. No. 488,035, issued to Blatt, discloses a honeycomb reinforcement core for a frame slat.
All of the above prior frame slats while having some increased stiffness are of the typical tubular construction and are not entirely satisfactory. The heddle supporting rod is affixed as a separate depending member to the frame slat rendering it vulnerable to loosening and fatigue.